1. Field of the Invention
The present invention relates to a Multiple Input Multiple Output (MIMO) technique, and more particularly, to a Multiple Input Multiple Output (MIMO) receiver for detecting a transmission signal through QR decomposition of MIMO channel information, and a signal detection method thereof.
2. Description of the Related Art
Current wireless communication systems focus on transmitting high quality, large capacity multimedia data at a limited frequency range. Techniques for transmitting a large amount of data using a limited frequency range have been developed, and a representative technique among such techniques is a Multiple Input Multiple Output (MIMO) system.
A MIMO system includes a plurality of antennas at its transmitting and receiving terminals to form a plurality of independent fading channels, and transmits different signals through the respective transmitting antennas, thereby greatly improving data transmission speed. Therefore, the MIMO system can transmit a large amount of data without having to increase the number of available frequency bands.
MIMO systems can be classified into a Diagonal Bell Labs Layered Space-Time (D-BLAST) MIMO system and a Vertical Bell Labs Layered Space-Time (V-BLAST) MIMO system.
The D-BLAST MIMO system can obtain spatial multiplexing gain and transmission/reception multiplexing gain, but cannot be easily implemented. The V-BLAST MIMO system has been developed to improve the complexity in implementing the D-BLAST MIMO system. The V-BLAST MIMO system can obtain spatial multiplexing gain and reception diversity gain with relatively low complexity.
The V-BLAST MIMO system utilizes Successive Interference Cancellation (hereinafter, referred to as “SIC”) in order to detect a transmission signal received through a MIMO channel. The SIC technique multiples a received signal vector by a zero-forcing nulling vector, thus nulling interference.
However, the SIC technique has to calculate pseudo-inverse matrixes several times. Therefore, as the number of antennas increases, calculations become complicated, which makes implementation of a MIMO system difficult.